GuardAPI Logo
GuardAPI

Fix Broken User Authentication in Hapi

Broken authentication is the #1 target for credential stuffing and session hijacking. In Hapi, vulnerabilities usually manifest as weak hashing algorithms, manual session management, or failure to leverage the internal auth ecosystem. If you're comparing MD5 hashes in a route handler, your app is already compromised. We're moving to Argon2 for hashing and @hapi/cookie for robust, encrypted session management.

The Vulnerable Pattern

const Hapi = require('@hapi/hapi');
const md5 = require('md5');

const server = Hapi.server({ port: 3000 });


server.route({
method: ‘POST’,
path: ‘/login’,
handler: async (request, h) => {
const { username, password } = request.payload;
const user = await db.getUser(username);


// VULNERABLE: Using MD5 (fast, crackable) and manual session handling
if (user && user.password === md5(password)) {
  return { status: 'authenticated', sessionId: user.id };
}
return h.response('Unauthorized').code(401);


}
});

The Secure Implementation

The fix eliminates custom, weak logic. First, we replace MD5 with Argon2, which is memory-hard and resistant to GPU cracking. Second, we integrate @hapi/cookie to handle session state. This ensures session tokens are encrypted, HttpOnly (preventing XSS-based theft), and Secure (enforcing HTTPS). By using Hapi's native 'server.auth.strategy', we centralize authentication logic, ensuring that validation is consistent across all routes and reducing the attack surface for session fixation.

const Hapi = require('@hapi/hapi');
const Cookie = require('@hapi/cookie');
const Argon2 = require('argon2');

const start = async () => {
const server = Hapi.server({ port: 3000 });
await server.register(Cookie);


server.auth.strategy(‘session’, ‘cookie’, {
cookie: {
name: ‘sid’,
password: ‘mypassword-must-be-32-chars-long-minimum’,
isSecure: true,
isHttpOnly: true,
path: ’/’,
ttl: 24 * 60 * 60 * 1000
},
validateFunc: async (request, session) => {
const user = await db.getUserById(session.id);
return { isValid: !!user, credentials: user };
}
});


server.route({
method: ‘POST’,
path: ‘/login’,
options: { auth: false },
handler: async (request, h) => {
const { username, password } = request.payload;
const user = await db.getUser(username);


  if (user && await Argon2.verify(user.password_hash, password)) {
    request.cookieAuth.set({ id: user.id });
    return { status: 'success' };
  }
  return h.response('Invalid credentials').code(401);
}


});
};

System Alert • ID: 9912
Target: Hapi API
Potential Vulnerability

Your Hapi API might be exposed to Broken User Authentication

74% of Hapi apps fail this check. Hackers use automated scanners to find this specific flaw. Check your codebase before they do.

RUN FREE SECURITY DIAGNOSTIC
GuardLabs Engine: ONLINE

Free Tier • No Credit Card • Instant Report

Verified by Ghost Labs Security Team

This content is continuously validated by our automated security engine and reviewed by our research team. Ghost Labs analyzes over 500+ vulnerability patterns across 40+ frameworks to provide up-to-date remediation strategies.

About GuardLabs → Follow us on X